Yes you're raising the centre of gravity when the bike is on two wheels, so yes it will be slightly more unstable. As Dave has said bar/stem set up makes a large difference to how much of a difference a high BB makes.
But with respect to your comment " So isn't that supposed to feel like riding a mod with +146mm bb"... No, there are many other geometry factors that affect how the bike rides and feels, so it's not as simple as what you've asked.